He is best known for his book, the Muqaddimah or Prolegomena ("Introduction"). The book influenced 17th-century Ottoman historians like Kâtip Çelebi, Ahmed Cevdet Pasha and Mustafa Naima who used the theories in the book to analyze the growth and decline of the Ottoman Empire.[10] 19th-century European scholars also acknowledged the significance of the book and considered Ibn Khaldun as one of the greatest philosophers of the Middle Ages.[11]

Ibn Khaldun's life is relatively well-documented, as he wrote an autobiography (التعريف بابن خلدون ورحلته غربا وشرقا, at-Taʻrīf bi-ibn Khaldūn wa-Riḥlatih Gharban wa-Sharqan[13]) in which numerous documents regarding his life are quoted word-for-word.

Abdurahman bin Muhammad bin Muhammad bin Muhammad bin Al-Hasan bin Jabir bin Muhammad bin Ibrahim bin Abdurahman bin Ibn Khaldun, generally known as "Ibn Khaldūn" after a remote ancestor, was born in Tunis in AD 1332 (732 A.H.) into an upper-class Andalusian family of Arab descent,[8] the family's ancestor was, according to him, a Yemenite Arab who shared kinship with Waíl ibn Hujr, a companion of the Islamic ProphetMuhammad. His family, which held many high offices in Andalusia, had emigrated to Tunisia after the fall of Seville to the Reconquista in AD 1248. Under the Tunisian Hafsid dynasty some of his family held political office; Ibn Khaldūn's father and grandfather however withdrew from political life and joined a mystical order. His brother, Yahya Khaldun, was also a historian who wrote a book on the Abdalwadid dynasty, and who was assassinated by a rival for being the official historiographer of the court.[14]

In his autobiography, Khaldun traces his descent back to the time of Muhammad through an Arab tribe from Yemen, specifically the Hadhramaut, which came to the Iberian Peninsula in the eighth century at the beginning of the Islamic conquest. In his own words: "And our ancestry is from Hadhramaut, from the Arabs of Yemen, via Wa'il ibn Hujr also known as Hujr ibn 'Adi, from the best of the Arabs, well-known and respected." (p. 2429, Al-Waraq's edition). However, the biographer Mohammad Enan questions his claim, suggesting that his family may have been Muladis who pretended to be of Arab origin in order to gain social status.[15] Enan also mentions a well documented past tradition, concerning certain Berber groups, whereby they delusively "aggrandize" themselves with some Arab ancestry. The motive of such an invention was always the desire for political and societal ascendancy. Some speculate this of the Khaldun family; they elaborate that Ibn Khaldun himself was the product of the same Berber ancestry as the native majority of his birthplace. A point congenial to this posits that Ibn Khaldun's unusual written focus on, and admiration for Berbers reveals a deference towards them that is born of a vested interest in preserving them in the realm of conscious history. Islamic scholar Muhammad Hozien contends that "The false [Berber] identity would be valid however at the time that Ibn Khaldun’s ancestors left Andulsia and moved to Tunisia they did not change their claim to Arab ancestry. Even in the times when Berbers were ruling, the reigns of Al-Marabats and al-Mowahids, et. al. The Ibn Khalduns did not reclaim their Berber heritage".[16] Khaldun's tracing of his own genealogy and surname are thought to be the strongest indication of Arab Yemenite ancestry.<ref="WP:BOMBARD"/>[17]

Following family tradition, Ibn Khaldūn strove for a political career. In the face of a tumultuous political situation in North Africa, this required a high degree of skill developing and dropping alliances prudently, to avoid falling with the short-lived regimes of the time.[citation needed] Ibn Khaldūn's autobiography is the story of an adventure, in which he spends time in prison, reaches the highest offices and falls again into exile.[citation needed]

At the age of 20, he began his political career at the Chancellery of the Tunisian ruler Ibn Tafrakin with the position of Kātib al-'Alāmah, which consisted of writing in fine calligraphy the typical introductory notes of official documents. In 1352, Abū Ziad, the Sultan of Constantine, marched on Tunis and defeated it. Ibn Khaldūn, in any case unhappy with his respected but politically meaningless position, followed his teacher Abili to Fez. Here the Marinid sultan Abū Inan Fares I appointed him as a writer of royal proclamations, which didn't prevent Ibn Khaldūn from scheming against his employer. In 1357 this brought the 25-year-old a 22-month prison sentence. Upon the death of Abū Inan in 1358, the vizier al-Hasān ibn-Umar granted him freedom and reinstated him in his rank and offices. Ibn Khaldūn then schemed against Abū Inan's successor, Abū Salem Ibrahim III, with Abū Salem's exiled uncle, Abū Salem. When Abū Salem came to power, he gave Ibn Khaldūn a ministerial position, the first position which corresponded with Ibn Khaldūn's ambitions.

The treatment Ibn Khaldun received after the fall of Abū Salem through Ibn-Amar ʻAbdullah, a friend of Ibn Khaldūn's, was not to his liking, he received no significant official position. At the same time, Amar successfully prevented Ibn Khaldūn – whose political skills he was well aware of – from allying with the Abd al-Wadids in Tlemcen. Ibn Khaldūn therefore decided to move to Granada. He could be sure of a positive welcome there, since at Fez he had helped the Sultan of Granada, the Nasrid Muhammad V, regain power from his temporary exile. In 1364 Muhammad entrusted him with a diplomatic mission to the King of Castile, Pedro the Cruel, to endorse a peace treaty. Ibn Khaldūn successfully carried out this mission, and politely declined Pedro's offer to remain at his court and have his family's Spanish possessions returned to him.

In Granada, Ibn Khaldūn quickly came into competition with Muhammad's vizier, Ibn al-Khatib, who saw the close relationship between Muhammad and Ibn Khaldūn with increasing mistrust. Ibn Khaldūn tried to shape the young Muhammad into his ideal of a wise ruler, an enterprise which Ibn al-Khatib thought foolish and a danger to peace in the country – and history proved him right. At al-Khatib's instigation, Ibn Khaldūn was eventually sent back to North Africa. Al-Khatib himself was later accused by Muhammad of having unorthodox philosophical views, and murdered, despite an attempt by Ibn Khaldūn to intercede on behalf of his old rival.

In his autobiography, Ibn Khaldūn tells us little about his conflict with Ibn al-Khatib and the reasons for his departure. The orientalist Muhsin Mahdi interprets this as showing that Ibn Khaldūn later realised that he had completely misjudged Muhammad V.

Back in Africa, the Hafsid sultan of Bougie, Abū ʻAbdallāh, (who had been his companion in prison) received him with great enthusiasm, and made Ibn Khaldūn his prime minister. During this period, Ibn Khaldūn carried out a daring mission to collect taxes among the local Berber tribes. After the death of Abū ʻAbdallāh in 1366, Ibn Khaldūn changed sides once again and allied himself with the Sultan of Tlemcen, Abū l-Abbas. A few years later he was taken prisoner by Abu Faris Abdul Aziz, who had defeated the sultan of Tlemcen and seized the throne. He then entered a monastic establishment, and occupied himself with scholastic duties, until in 1370 he was sent for to Tlemcen by the new sultan. After the death of ʻAbdu l-Azīz, he resided at Fez, enjoying the patronage and confidence of the regent.

Ibn Khaldūn's political skills, above all his good relationship with the wild Berber tribes, were in high demand among the North African rulers, whereas he himself began to tire of politics and constant switching of allegiances. In 1375, sent by Abū Hammu, the ʻAbdu l Wadid Sultan of Tlemcen, on a mission to the Dawadida Arabs tribes of Biskra. After his return to the West Ibn Khaldūn sought refuge with one of the Berber tribes, in the west of Algeria, in the town of Qalat Ibn Salama. He lived there for over three years under their protection, taking advantage of his seclusion to write the Muqaddimah "Prolegomena", the introduction to his planned history of the world. In Ibn Salama, however, he lacked the necessary texts to complete the work. As a result, in 1378, he returned to his native Tunis, which in the mean time had been conquered by Abū l-Abbas, who took Ibn Khaldūn back into his service. There he devoted himself almost exclusively to his studies and completed his history of the world. His relationship with Abū l-Abbas remained strained, as the latter questioned his loyalty. This was brought into sharp contrast after Ibn Khaldūn presented him with a copy of the completed history omitting the usual panegyric to the ruler. Under pretence of going on the Hajj to Mecca – something a Muslim ruler could not simply refuse permission for – Ibn Khaldūn was able to leave Tunis and sail to Alexandria.

Ibn Khaldun said of Egypt, "He who has not seen it does not know the power of Islam."[this quote needs a citation] While other Islamic regions had to cope with border wars and inner strife, under the Mamluks Egypt experienced a period of economic prosperity and high culture. However, even in Egypt, where Ibn Khaldūn lived out his days, he could not stay out of politics completely. In 1384 the Egyptian Sultan, al-Malik udh-Dhahir Barquq, made him Professor of the Qamhiyyah Madrasah, and grand Qadi of the Maliki school of fiqh (one of four schools, the Maliki school was widespread primarily in West Africa). His efforts at reform encountered resistance, however, and within a year he had to resign his judgeship. A contributory factor to his decision to resign may have been the heavy personal blow that struck him in 1384, when a ship carrying his wife and children sank off the coast of Alexandria. Ibn Khaldun now decided to complete the pilgrimage to Mecca after all.

After his return in May 1388, Ibn Khaldūn concentrated more strongly on a purely educational function at various Cairo madrasas. At court he fell out of favor for a time, as during revolts against Barquq he had – apparently under duress – together with other Cairo jurists issued a Fatwa against Barquq. Later relations with Barquq returned to normal, and he was once again named the Maliki qadi. Altogether he was called six times to this high office, which for various reasons he never held long.

In 1401, under Barquq's successor, his son Faraj, Ibn Khaldūn took part in a military campaign against the Mongol conqueror Timur, who besieged Damascus. Ibn Khaldūn cast doubt upon the viability of the venture and didn't really want to leave Egypt. His doubts were vindicated, as the young and inexperienced Faraj, concerned about a revolt in Egypt, left his army to its own devices in Syria and hurried home. Ibn Khaldūn remained at the besieged city for seven weeks, being lowered over the city wall by ropes in order to negotiate with Timur, in a historic series of meetings which he reports extensively in his autobiography. Timur questioned him in detail about conditions in the lands of the Maghreb; at his request, Ibn Khaldūn even wrote a long report about it. As he recognized the intentions behind this, he did not hesitate, on his return to Egypt, to compose an equally extensive report on the history of the Tartars, together with a character study of Timur, sending these to the Merinid rulers in Fez (Maghreb).

Ibn Khaldūn spent the following five years in Cairo completing his autobiography and his history of the world and acting as teacher and judge. During this time, he is alleged to have joined an underground party named Rijal Hawa Rijal. Their reform oriented ideals attracted the attention of local political authorities and the elderly Ibn Khaldun was placed under arrest. He died on 19 March 1406, one month after his sixth selection for the office of the Maliki qadi (Judge).

Ibn Khaldūn main work is the Kitāb al-ʻIbar or "Book of Lessons" (full title: Kitāb al-ʻIbar wa-Dīwān al-Mubtadaʼ wa-l-Khabar fī Taʼrīkh al-ʻArab wa-l-Barbar wa-Man ʻĀṣarahum min Dhawī ash-Shaʼn al-Akbār "Book of Lessons, Record of Beginnings and Events in the History of the Arabs and the Berbers and Their Powerful Contemporaries"), originally conceived as a history of the Berbers but later expanded in focus to a universal history.

The Kitāb al-ʻIbār is divided into seven books, the first of which, the Muqaddimah or "Introduction", can be considered a separate work. Books two to five cover the history of mankind up to the time of Ibn Khaldūn. Books six and seven cover the history of the Berber peoples and the Maghreb. The work is an important source for Berber history, although Ibn Khaldun in parts relied on poor source material (e.g. the Rawḍ al-Qirṭās). His historiographical work has been criticised for often presenting only a synthesis of multiple (sometimes contradictory) sources where a more careful historian such as ar-Raqīq or al-Mālikī would always give the original texts before pronouncing an opinion.[19]

Concerning the discipline of sociology, he conceived a theory of social conflict. He developed the dichotomy of sedentary life versus nomadic life as well as the concept of a "generation", and the inevitable loss of power that occurs when desert warriors conquer a city. Following a contemporary Arab scholar, Sati' al-Husri, the Muqaddimah may be read as a sociological work. Topics dealt with in this work include politics, urban life, economics, and knowledge. The work is based around Ibn Khaldun's central concept of 'aṣabiyyah, which has been translated as "social cohesion", "group solidarity", or "tribalism". This social cohesion arises spontaneously in tribes and other small kinship groups; it can be intensified and enlarged by a religious ideology. Ibn Khaldun's analysis looks at how this cohesion carries groups to power but contains within itself the seeds – psychological, sociological, economic, political – of the group's downfall, to be replaced by a new group, dynasty or empire bound by a stronger (or at least younger and more vigorous) cohesion. Ibn Khaldun has been cited as a racist, but his theories on the rise and fall of empires have no racial component, and this reading of his work has been claimed to be the result of mistranslations.[20]

Perhaps the most frequently cited observation drawn from Ibn Khaldūn's work is the notion that when a society becomes a great civilization (and, presumably, the dominant culture in its region), its high point is followed by a period of decay. This means that the next cohesive group that conquers the diminished civilization is, by comparison, a group of barbarians. Once the barbarians solidify their control over the conquered society, however, they become attracted to its more refined aspects, such as literacy and arts, and either assimilate into or appropriate such cultural practices. Then, eventually, the former barbarians will be conquered by a new set of barbarians, who will repeat the process. Some contemporary readers of Khaldun have read this as an early business cycle theory, though set in the historical circumstances of the mature Islamic empire.[who?][dubious– discuss]

Ibn Khaldun outlines an early (possibly even the earliest) example of political economy. He describes the economy as being composed of value-adding processes; that is, labour and skill is added to techniques and crafts and the product is sold at a higher value. He also made the distinction between "profit" and "sustenance", in modern political economy terms, surplus and that required for the reproduction of classes respectively. He also calls for the creation of a science to explain society and goes on to outline these ideas in his major work the Muqaddimah.

Ibn Khaldun also emphasized on the Islamic Monetary System that the currency or money should have intrinsic value. And it should be made up of Gold and Silver i.e. Gold dinar and SilverDirham. He also emphasized that the weight and purity of these coins should be strictly followed. As the weight of one dinar should be one mithqal i.e. equal the weight of 72 grains of barley (equals to almost 4.25 grams) and the weight of 7 dinar should be equal to weight of 10 Dirhams (which equal 7/10 of Mithqal or 2.975 grams). And according to him these coins must be used in laws concerning the charity tax (Zakat), marriage (fees), fixed legal fines, and other things.[21]

A possible non-symmetric Laffer Curve with a maximum revenue point at around a 70% tax rate, based on "How Far Are We From The Slippery Slope?,[22] Laffer cites Ibn Khaldun's observation that "at the beginning of the dynasty, taxation yields a large revenue from small assessments. At the end of the dynasty, taxation yields a small revenue from large assessments." as a predecessor.[23][24]

Ibn Khaldun was first brought to the attention of the Western world in 1697, when a biography of him appeared in Barthélemy d'Herbelot de Molainville's Bibliothèque Orientale. Ibn Khaldun began gaining more attention from 1806, when Silvestre de Sacy's Chrestomathie Arabe included his biography together with a translation of parts of the Muqaddimah as the Prolegomena.[25] In 1816, de Sacy again published a biography with a more detailed description on the Prolegomena.[26] More details on and partial translations of the Prolegomena emerged over the years until the complete Arabic edition was published in 1858. Since then, the work of Ibn Khaldun has been extensively studied in the Western world with special interest.[27]

The British philosopher Robert Flint wrote the following on Ibn Khaldun: "as a theorist of history he had no equal in any age or country until Vico appeared, more than three hundred years later. Plato, Aristotle, and Augustine were not his peers, and all others were unworthy of being even mentioned along with him".

Abderrahmane Lakhsassi writes: "No historian of the Maghreb since and particularly of the Berbers can do without his historical contribution."[29]

The British philosopher-anthropologist Ernest Gellner considered Ibn Khaldun's definition of government, "an institution which prevents injustice other than such as it commits itself", the best in the history of political theory.[30]

Egon Orowan, who termed the concept of socionomy, was influenced by Ibn Khaldun's ideas on the evolution of societies.[31]

In 2004, the Tunisian Community Center launched the first Ibn Khaldun Award to recognize a Tunisian/American high achiever whose work reflects Ibn Khaldun's ideas of kinship and solidarity. The Award was named after Ibn Khaldun for him being universally acknowledged as the Father of Sociology and also for the convergence of his ideas with the organization's objectives and programs.

In 2006, the Atlas Economic Research Foundation launched an annual essay contest [1] for students named in Ibn Khaldun's honor. The theme of the contest is "how individuals, think tanks, universities and entrepreneurs can influence government policies to allow the free market to flourish and improve the lives of its citizens based on Islamic teachings and traditions."[this quote needs a citation]

In 2006, Spain commemorated the 600th anniversary of the death of Ibn Khaldun. [2]

When civilization [population] increases, the available labor again increases. In turn, luxury again increases in correspondence with the increasing profit, and the customs and needs of luxury increase. Crafts are created to obtain luxury products. The value realized from them increases, and, as a result, profits are again multiplied in the town. Production there is thriving even more than before. And so it goes with the second and third increase. All the additional labor serves luxury and wealth, in contrast to the original labor that served the necessity of life.[4]

One should then look at the world of creation. It started out from the minerals and progressed, in an ingenious, gradual manner, to plants and animals. The last stage of minerals is connected with the first stage of plants, such as herbs and seedless plants. The last stage of plants, such as palms and vines, is connected with the first stage of animals, such as snails and shellfish which have only the power of touch. The word "connection" with regard to these created things means that the last stage of each group is fully prepared to become the first stage of the next group.

The animal world then widens, its species become numerous, and, in a gradual process of creation, it finally leads to man, who is able to think and to reflect. The higher stage of man is reached from the world of the monkeys, in which both sagacity and perception are found, but which has not reached the stage of actual reflection and thinking. At this point we come to the first stage of man after (the world of monkeys). This is as far as our (physical) observation extends.[33]

The dirham and the dinar differ in value and weight in different regions, cities, and provinces. The religious law has had occasion to refer to these (coins) and has mentioned them in connection with many laws concerning the charity tax, marriage (fees), fixed legal fines, and other things. Therefore, the religious law must have its own (dirham and dinar) with a specific value given to them by (the religious law itself) and agreeing with the intention of (the religious law). These coins are then the ones to which the laws refer. They are different from the non-legal (coins).[34]

Ibn Khaldun on Islamic Monetary Economics

The Revelation undertook to mention them and attached many judgements to them, for example zakat, marriage, and hudud, etc., therefore within the Revelation they have to have a reality and specific measure for assessment of zakat, etc. upon which its judgements may be based rather than on the non-shari'i other coins.

Know that there is consensus since the beginning of Islam and the age of the Companions and the Followers that the dirham of the shari'ah is that of which ten weigh seven mithqals weight of the dinar of gold... The weight of a mithqal of gold is seventy-two grains of barley, so that the dirham which is seven-tenths of it is fifty and two-fifths grains. All these measurements are firmly established by consensus[35]

"This grand scheme to find a new science of society makes him the forerunner of many of the eighteenth and nineteenth centuries system-builders such as Vico, Comte and Marx." "As one of the early founders of the social sciences...".[38]

"He is considered by some as a father of modern economics, or at least a major forerunner. The Western world recognizes Khaldun as the father of sociology but hesitates in recognizing him as a great economist who laid its very foundations. He was the first to systematically analyze the functioning of an economy, the importance of technology, specialization and foreign trade in economic surplus and the role of government and its stabilization policies to increase output and employment. Moreover, he dealt with the problem of optimum taxation, minimum government services, incentives, institutional framework, law and order, expectations, production, and the theory of value".Cosma, Sorinel (2009). "Ibn Khaldun's Economic Thinking". Ovidius University Annals of Economics (Ovidius University Press) XIV:52–57

^ abSavant, Sarah Bowen (2014). Genealogy and Knowledge in Muslim Societies: Understanding the Past. Edinburgh University Press. p. 77. ISBN978-0748644971. Banu Khaldun al-Hadrami (Yemen, but not Qahtan), to which belonged the famous historian Ibn Khaldun. The family's ancestor was 'Uthman ibn Bakr ibn Khalid, called Khaldun, a Yemeni Arab among the conquerors who shared kinship with the Prophet's Companian Wa'il ibn Hujr and who settled first in Carmona and then in Seville.The Historical Muhammad, Irving M. Zeitlin, (Polity Press, 2007), 21; "It is, of course, Ibn Khaldun as an Arab here speaking, for he claims Arab descent through the male line.". The Arab World: Society, Culture, and State, Halim Barakat, (University of California Press, 1993), 48;"The renowned Arab sociologist-historian Ibn Khaldun first interpreted Arab history in terms of badu versus hadar conflicts and struggles for power." Ibn Khaldun, M. Talbi, The Encyclopaedia of Islam, Vol. III, ed. B. Lewis, V.L. Menage, C. Pellat, J. Schacht, (Brill, 1986), 825;"Ibn Khaldun was born in Tunis, on I Ramadan 732/27 May 1332, in an Arab family which came originally from the Hadramawt and had been settled at Seville since the beginning of the Muslim conquest..."